I'm having trouble with a few of my homework problems this evening. *sigh*

1. Find all real solutions of x4 - 7x3 + 7x² + 21x - 30 = 0

and

2. Find a mathematical model representing the statement. (In each case determine the constant of proportionality.)

F varies directly as x and inversely as y, and F = 500 when x = 15 and y = 2

I thought number one would be easy. I guess I was wrong.